In an orthopaedic context, traction is a mechanism for relieving pressure on the spine. It has been shown that the ideal level of neck traction is related to the body-weight of a person.
Existing devices include pulley systems that attach to a door and comprise a sling in which a user positions their chin. The sling is connected using a rope and via a pulley to a bladder, which is filled with water or other liquid to provide a force to ‘pull’ the head in a direction away from the shoulders. Problems with this device may arise if the sling is positioned incorrectly or if the user fills the bladder with too much liquid. This may result in damage to the user's neck. In variations on this pulley device, the bladder may not be present and the user pulls on the rope to introduce the traction force. It is easy to use excessive force in such an embodiment.
Other methods include hanging one's head over the edge of a piece of furniture, and applying a weight to the chin and/or top of the head. Again, if the weight is too heavy, this may result in neck damage. Additionally, the head is unsupported, which may result in the force being applied unevenly or in a disadvantageous direction.
Inflatable devices are also known, which comprise a collar positioned around the user's neck. The collar is then inflated and expands in the longitudinal direction and provides a longitudinal traction force to the neck in the sagittal plane. Excessive pressure on the neck can be applied if the user continues to inflate the collar beyond the necessary amount. Additionally, the use of a hand pump can be awkward for some users.
Other devices include a two-piece ratcheting mechanism that can be used to apply an increased force as the ratcheting mechanism is operated.